Packaging machine having a sealing means

ABSTRACT

The present invention relates to a packaging machine comprising a sealing station which uses a sealing means to join an upper film web to a lower film web by sealing, said sealing means having at least one opening which is connected to a vacuum source and/or a source of substitute gas. The present invention also relates to a sealing frame.

The present invention relates to a packaging machine comprising a sealing station which uses a sealing means to seal an upper film web to a lower film web, said sealing means having at least one opening, connected to a vacuum source and/or to a source of substitute gas. The present, invention further relates to a sealing frame assembly.

Packaging machines of this type are well known from the prior art and are used, for instance, to close off a packaging tray, which is deep-drawn into the lower film web and has subsequently been filled, with a cover film, by sealing of the upper film to the lower film. In these packagings, prior to the closure, a gas exchange often takes place in and/or before the sealing station, i.e. the air or gas present inside the packaging is extracted by means of an underpressure and/or replaced, at least partially, by a substitute gas, which is introduced, in particular injected, between the upper and the lower film. Nowadays, these packaging machines generally produce per machine cycle several packagings simultaneously, in which the gas exchange is preferably intended to take place individually or identically.

It was therefore the object of the present invention to provide a packaging machine which meets these requirements.

The object is achieved with a packaging machine comprising a sealing station which uses a sealing means to seal an upper film web to a lower film web, said sealing means having at least one opening, connected to a vacuum source and/or to a source of substitute gas, wherein in the sealing means is provided at least one valve, with which the gas flow at the opening is adjustable.

The present invention relates to a packaging machine, in particular a form fill seal packaging machine (FFS packaging machine). In these packaging machines, a lower film web is transported, in particular in cycles, along the packaging machine, and firstly one or more packaging tray(s) is/are formed into the lower film web. Next, each packaging tray is filled in a filling station with a product to be packed, in particular food slices, or other weighable and/or countable products to be packed, in particular foodstuffs, and afterwards closed off with a cover film, which is fastened, in particular sealed, to the packaging tray. In a cycle, a multiplicity of packaging trays, substantially simultaneously, is preferably deep drawn, filled and provided with a cover film. This multiplicity of packaging trays is referred to as a so-called format, containing (X·Y) packaging trays.

The sealing of the upper film to the lower film is realized, under the influence of heat and pressure, with a sealing means. This sealing means is preferably a heated sealing frame, which predefines the shape of the sealing seam and which generally has for each packaging tray a recess which at least partially receives the packaging tray during the sealing process. The sealing frame seals the cover film simultaneously to all packaging trays of a format, is preferably provided beneath the lower film web, and is preferably raised for the sealing and preferably lowered after the sealing. When raised, the sealing frame is pressed against an upper tool, for instance a sealing frame or a plate. The two film webs, which are located between the sealing frame assembly and the upper tool, are here pressed one against the other and are sealed to each other under the influence of heat.

According to the invention, a sealing tool, in particular the sealing frame assembly, now has at least one opening, connected to a vacuum source and/or to a source of substitute gas. Through this opening, either air present between the two film webs is extracted and/or a substitute gas is injected between the two film webs. The openings extend preferably in a row running parallel to the transport direction of the lower film web. For gas exchange, at least one, preferably a multiplicity of holes, are made in the lower film web, preferably before the sealing station, through which holes the gas enters into the space between the two film webs or is sucked out of this same. Alternatively, the vacuum can also be introduced and/or the gas exchange realized by means of longitudinally and/or transversely disposed nozzles, so-called longitudinal and transverse nozzles, as disclosed, for instance, in DE 102006020360.

According to the invention, in the sealing means or at least one nozzle there is now provided a valve, with which the flow at the opening is adjustable, i.e. for instance volumetric rate of flow per unit of time, flow direction and/or flow velocity. In particular if a multiplicity of openings are present in the sealing means, the gas flow, i.e. the aspiration of the air and/or the injection of the substitute gas for each packaging tray of a format can be regulated individually or in groups. It is thereby possible for each format to receive in the packaging trays substantially the same gas atmosphere or to obtain specifically different conditions.

Preferably a conduit, for instance in the form of a bore, is provided in the tool, in particular in the sealing frame assembly, which conduit connects one or more openings to a vacuum source and/or source of substitute gas. In this conduit is now provided a valve, with which the cross section of the conduit at the site of the valve can be altered in order to adjust the flow resistance, and thus the quantity of gas which is sucked into the opening or blown out of the opening, or the flow velocity of the gas. Targeted adjustment of the flow velocity of the gas can be used, for instance, to prevent products which are light and/or have a tendency to move, slip, or even to fly away, such as, for instance, sausage slices with low fat content and low mutual adhesive effect, from moving and/or flying away.

Preferably, a blind hole, into which a cylinder having a through bore is introduced, is provided in the conduit. The through bore can be fully or only partially aligned with the conduit and thereby alter the flow cross section. It is also possible, however, to screw into the blind hole a screw, or a valve tappet, which alters the cross section of the blind hole, and thus of the conduit.

The valve can be driven by manual or motorized means.

The adjustment of each valve can be realized automatically, by a sensor, for instance, measuring the atmosphere in the packaging or the flow velocity at the opening and then adjusting the respective valve accordingly.

Preferably, the sealing tool, in particular the sealing frame assembly, has a multiplicity of openings, the flow of which is at least partially, preferably fully, individually adjustable.

Preferably, the valve has a locking means, which locks it in its respective position, so that it does not independently shift during operation of the packaging machine. A locking means of this type is, for instance, a varnish.

A further subject of the present invention is a sealing frame assembly, having an opening connected to a conduit, wherein in the conduit is provided a valve, with which a gas stream out of or into the opening is adjustable.

The statements made with regard to this subject of the present invention apply equally to the packaging machine according to the invention, and vice versa.

Preferably, the sealing frame assembly has a multiplicity of openings, which are preferably provided on mutually opposite sides, in particular along a line.

Preferably, each opening is connected to a gas conduit, which is preferably incorporated, in particular by drilling, into the wall of the sealing frame assembly. Each gas conduit is connected to a vacuum source and/or source of substitute gas. In each of these conduits is provided a valve, with which the gas stream through the respective conduit can be adjusted.

Preferably, in each conduit is provided a blind hole, which serves as a seat for a valve body, for instance a cylinder, or into which a valve body can be screwed.

A further subject of the present invention is a nozzle, preferably a transverse and/or longitudinal nozzle, having one or more openings connected to a conduit, wherein in one or each conduit is provided a valve, with which a gas stream out of or into the opening is adjustable.

The statements made with regard to this subject of the present invention apply equally to the packaging machine according to the invention, and vice versa.

Below, the inventions ere described with reference to FIGS 1 to 3. These comments are merely illustrative and do not limit the general inventive concept. The comments apply equally to all subjects of the present invention.

FIG. 1 shows the packaging machine according to the invention.

FIG. 2 shows the sealing means, here a sealing frame assembly.

FIG. 3 shows a valve.

FIG. 1 shows the packaging machine 1 according to the invention, which has a deep drawing station 2, a filling station 7 and a sealing station 15. A lower film web 8, here a plastics film web 8, is unreeled from a supply roll and is transported in cycles from right to left along the packaging machine according to the invention. In a cycle, the lower film web 8 is transported onward by one format length. For this, the packaging machine has two transport means (not represented), in the present case respectively two continuous chains, which are disposed to the right and left of the lower film web 8. Both at the start and at the end of the packaging machine there is respectively provided for each chain at least one gearwheel, around which the respective chain is looped. At least one of these gearwheels is driven. The gearwheels in the inlet region and/or in the outlet region can be connected to each other, preferably by a rigid shaft. Each transport means has a multiplicity of clamping means, which clampingly grasp the lower film web 8 in the infeed region 19 and transmit the movement of the transport means to the lower film web 8. In the outfeed region of the packaging machine, the clamping connection between the transport means and the lower film web 8 is released again. Downstream of the infeed region 19 is provided a heating means 13, which heats the film web 8, in particular when this is stationary. In the deep drawing station 2, which possesses an upper tool 3 and a lower tool 4, which latter has the shape of the packaging tray to be produced, the packaging trays 6 are formed into the warmed film web 8. The lower tool 4 is disposed on a lifting table 5, which, as is symbolized by the double arrow, is vertically adjustable. Prior to each film advancement, the lower tool 4 is lowered and afterwards is raised again. Further along the packaging machine, the packaging trays are then filled in the filling station 7 with the product to be packed 16. In the following sealing station 15, which likewise consists of an upper tool 12 and a vertically adjustable lower tool 11, an upper film 14 is integrally fastened, by sealing, to the lower film web 8. In the sealing station too, the upper tool and/or the lower tool, before and after each film transport, are raised and lowered respectively. Also the upper film 14 can be guided in transport means or be transported by transport chains, wherein these transport means then extend only from the sealing station and, if necessary, downstream. Otherwise the statements which were made with regard to the transport means of the lower film apply. The upper film too can be warmed with a heating means and deep drawn. For the sealing, a heatable sealing frame, for instance, which for each packaging tray has an opening into which the packaging tray intrudes during the sealing process, i.e. upon the upward movement of the lower sealing tool, is provided as the lower tool 11. For the sealing, the upper and the lower film web are pressed together between the upper and the lower tool 12, 11 and are joined under the influence of heat and pressure. Following the sealing, the tools 11, 12 are moved vertically apart again. Before and/or during the sealing of the upper film to the lower film, a gas exchange takes place in each packaging tray. For this, the air present in the packaging tray is firstly partially extracted and then replaced by a substitute gas. For this, in the region of each format, holes are made in the lower film in the region of the transport chains, in the lower film web, through which holes the air between the film webs 8, 14 is extracted and the substitute gas is then injected. Further along the packaging machine, the completed packagings are singularized, which in the present case is realized with the transverse cutter 18 and the longitudinal cutter 17. In the present case, the transverse cutter 18 is likewise raisable and lowerable with a lifting device 9.

FIG. 2 shows details of the sealing frame assembly 20, which in the present case constitutes the lower tool 11. This sealing frame assembly is heated for sealing purposes and consequently has heating means (not represented). In its marginal region, the sealing frame assembly has a multiplicity of openings 22, through which air can flow in or a substitute gas can flow out. These openings 22 are respectively connected to a conduit 21, which is incorporated, here drilled, into the sealing frame assembly and which connects each opening 22 to a vacuum source and/or to a source of substitute gas. In the conduit 21 is respectively provided a valve, with which the gas stream out of the opening 22 or into the opening 22 can be adjusted or regulated. In the present case, the valve is provided as a blind hole in the conduit 21, which blind hole serves as a valve seat for a valve body 23, here a cylindrical body having a through bore 25. The body has a seal 26, here an O-ring seal, and is arranged in the blind hole such that the through bore 25 can be aligned with the conduit 21 when the valve is intended to be fully open. By clockwise or counterclockwise rotation of the valve body, the overlap of the through bore 25 and the conduit 21 is reduced, so that the flow through the conduit 21 is thereby reduced. A complete shutoff of the gas stream is also possible. In the present case, the valve body has a slot, which can receive the tip of a screwdriver with which the adjustment of the valve is realized. With the optionally present fastening means 24, the valve is secured against falling out and, following adjustment of the desired flow, the valve is secured, for instance with locking varnish, preferably against displacement.

FIG. 3 shows the valve body 23 in detail. 

1. A packaging machine comprising: a sealing station which uses a sealing means to seal an upper film web to a lower film web, the sealing means having at least one opening connected to a vacuum source and/or to a source of substitute gas, wherein the sealing means or a nozzle in the sealing station includes at least one valve with which a flow at the at least one opening is adjustable.
 2. The packaging machine as claimed in claim 1, wherein the sealing means is a sealing frame assembly.
 3. The packaging machine as claimed in claim 1, wherein the sealing means has a multiplicity of openings the flow of which is at least partially or fully, individually adjustable.
 4. The packaging machine as claimed in claim 1, wherein the at least one valve is drivable by a manual or a motorized means.
 5. (canceled)
 6. (canceled)
 7. The packaging machine as claimed in claim 1, wherein the at least one opening is connected to a conduit that connects the at least one opening to fee vacuum source and to the source of substitute gas, wherein the valve has a through bore that when fully aligned with the conduit provides for the valve to be fully opened. 8) The packaging machine as claimed in claim 7, wherein the valve is rotatable so that an overlap of the through bore and the conduit reduces flow through the conduit.
 9. A packaging machine comprising: a sealing station having a sealing means for sealing an upper film web to a lower film web, the sealing means having an opening connected to a vacuum source and to a source of substitute gas, wherein the sealing means includes a valve for adjusting air moving out of the opening gas moving into the opening, wherein a gas exchange takes place where the air moving out of the opening is extracted from between the upper film web and the lower film web, and the gas moving into the opening is injected between the upper film web and the lower film web, and wherein the gas exchange takes place before or during the sealing of the upper film web to the lower film web. 10) The packaging machine as claimed in claim 9, wherein the sealing means has multiple valves and multiple openings, wherein each of the valves are adjustable so that the air moving out of the openings or the gas moving into the openings can be adjusted so that the volumetric rate of flow per unit of time, flow direction and/or flow velocity is adjustable. 11) The packaging machine as claimed in claim 10, wherein each of the valves include a slot for manually adjusting the valves. 12) The packaging machine as claimed in claim 10, wherein each of the valves has a locking means which locks each of the valves in a respective position so that the valves do not independently shift during operation of the packaging machine. 13) The packaging machine as claimed in claim 10, wherein the lower film web is deep drawn to form a packaging tray, and the upper film web is sealed to the packaging tray. 14) The packaging machine as claimed in claim 10, wherein the openings are arranged in a row running parallel to a transport direction of the lower film web. 15) The packaging machine as claimed in claim 10, wherein a multiplicity of holes are made in the lower film web during or before the upper film web is sealed to the lower film web, and wherein the air is extracted from between the upper film web and the lower film web through the holes and the gas is injected between the upper film web and the lower film web through the holes. 16) A packaging machine comprising: a sealing station having a sealing means for sealing an upper film web to a lower film web, the sealing means having a plurality of openings connected to a conduit which connects the openings to vacuum source and to a source of substitute gas, the conduit includes a plurality of valves, wherein a gas exchange takes place in the sealing station where air moving to the vacuum source is extracted out of the openings from between the upper film web and the lower film web, and the gas moving from the source of substitute gas into the opening is injected between the upper film web and the lower film web, wherein each of the valves are adjustable so that the air moving out of the openings or the gas moving into the openings can be adjusted so that the volumetric rate of flow per unit of time, flow direction and/or flow velocity can be regulated, and wherein the gas exchange takes place before or during the sealing of the upper film web to the lower film web. 17) The packaging machine as claimed in claim 16, wherein each of the valves have a through bore that when fully aligned with the conduit provides for the valve to be fully opened, and wherein the valve is rotatable so that an overlap of the through bore and the conduit reduces flow through the conduit. 18) The packaging machine as claimed in claim 16, wherein the openings are arranged in a row running parallel to a transport direction of the lower film web. 19) The packaging machine as claimed in claim 18, wherein a multiplicity of holes, are made in the lower film web during or before the upper film web is sealed to the lower film web, and wherein the is extracted from between the upper film web and the lower film web through the holes, and the gas is injected between the upper film web and fee lower film web through the holes. 20) The packaging machine as claimed in claim 19, wherein the lower film web is deep drawn to form a packaging tray, and the upper film web is sealed to the packaging tray. 21) The packaging machine as claimed in claim 16, wherein each of the valves include an O-ring seal. 